FoM Flashcards
aa example with a helix as secondary structure
proline (remember H bonds)
most abundant protein in vertebrates
collagen
aa example with b sheets in secondary structure
proline + glycine (Remember H bonds)
secondary structure of collagen?
triple helix (3 left handed helicalchains) twisted around eahc other to form a R handed superhelix — Remember H bonds (inter chain H bonds) involving HYDROYLYSINE + HYDROXYPROLINE +++++ covalent inter and intra-moelxualr bonds—
repeating sequences in all strands X-Y-Glycine
X= any aa
Y= proline / hydroxyproline
+ hydroxylysine
why collagen important?
connective tissue – weakened collagen results in bleeding gums — BC of lack of Vc
Why Vc is important ? (correlation to COLLAGEN)
Vc = ascorbic acid
ascorbic acid is needed to hydroxylate PROLINE
if PROLINE is not hydroxylated, hydroxyproline will be reduced
THUS, collagen is weakend without hydroxyproline (Hydroxyproline forms H bonds when in the secondary structure — required for the stabilisaiton of the triple helixat physiological temperatures
examples of fibrous proteins
Keratin (hair + wool)
Collagen of conenctive tissue (cartilage + bones + teeth + skin + blood vessels)
examples of globular proteins
Myoglobin
haemoglobin
which aa forms disulphide bonds?
Cysteine (redox reaction)
what is glutamic acid
negatively charged at physiological pHw
what is valine
hydrophobic
describe sickle cell anaemia. How it arises due to functional changes of aa
Single nucleotide sequence change.
conding region of the b chain of haemoglobin
valine instead of glutamic acid
haemoglobin polymerises under low O2 conditions –> rseulting in rigid, sickle sjape cells
blocking the blood flow in capillaries
describe the structure of haemoglobin
4 subunits
2a + 2b
each contains a haem group
eac hsubunit binds 1 oxygen molecule
which proteins have a qauternary strucutre?
those that have more than 1 polypeptide chain
name + charged aa
ARGININE
lysine
hystidine
